The present invention relates to a hand-operated drive-in power tool. These types of hand-operated drive-in power tools have a displaceably guided drive-in ram which can be used to drive the fastening elements into a substrate.
A generic drive-in power tool is known from German Patent Document No. DE 10 2006 000 202 A1. This drive-in power tool has a drive arrangement for a drive-in ram displaceably arranged in a guide, which has at least one drive element for the drive-in ram formed as an elastomer band that is tensible via a tensioning device. The tensioning device in this case includes an electric drive.
Because of the lower density of the elastomer band as compared, for example, to a steel spring and because of the longer acceleration path, greater drive-in speeds can be achieved with this drive-in power tool and thus greater drive-in energy. However, a known disadvantage of elastomer materials is its diminishing efficiency at low temperatures.
The object of the present invention is to improve a drive-in power tool of the foregoing type and also to guarantee a high drive-in energy at low temperatures.
According to the present invention, a heating device is provided in the drive-in power tool for the at least one elastomer drive element. The, or each, elastomer drive element at low temperatures, i.e., at temperatures less than 10° C. for example, can be brought via the heating device to a favorable operating temperature, e.g., within a range of approx. 10° to approx. 50° C., thereby guaranteeing optimum efficiency of the elastomer drive elements and thus a high drive-in energy even at low temperatures. At least one temperature sensor is advantageously provided for determining the device temperature, thereby enabling automatic switch-on of the heating device as a function of the measuring data from the temperature sensor.
Furthermore, it is advantageous if the at least one temperature sensor is connected to a control unit, via which the heating device is controllable, thereby making automatic control of the heating device possible in a simple manner.
Moreover, it is advantageous if the heating device has a number of heating elements corresponding to the number of elastomer drive elements, thereby making a uniform heating of the elastomer drive elements possible.
In addition, it is advantageous if the, or each, heating element is arranged adjacent to an associated elastomer drive element and running along its longitudinal extension, which makes it possible for the applied thermal energy to be used especially efficiently.
Furthermore, it can be advantageous if the heat radiation of the, or each, heating element is focused in the direction of the associated drive element, thereby further optimizing the use of energy.
Alternatively, the heating device could also use the waste heat from the sources of heat present in the drive-in power tool, such as, for example, a tensioning motor or power electronics. Furthermore, the heating device could also be designed such that it puts the, or each, elastomer drive element into an oscillating movement with low expansion of the drive element, thereby producing heating of the, or each, drive element through internal friction.
The invention is depicted in the drawings in an exemplary embodiment.